Structured pedestal for mtj containing devices

ABSTRACT

A magnetic tunnel junction (MTJ) containing device is provided that includes an undercut conductive pedestal structure having a concave sidewall positioned between a bottom electrode and a MTJ pillar. The geometric nature of such a conductive pedestal structure makes the pedestal structure unlikely to be resputtered and deposited on a sidewall of the MTJ pillar, especially the sidewall of the tunnel barrier of the MTJ pillar. Thus, electrical shorts caused by depositing resputtered conductive metal particles on the sidewall of the tunnel barrier of the MTJ pillar are substantially reduced.

BACKGROUND

The present application relates to a magnetic tunnel junction (MTJ)containing device and a method of forming the same. More particularly,the present application relates to a MTJ containing device that includesa conductive pedestal structure having a concave sidewall and locatedbetween a bottom electrode and a MTJ pillar.

Magnetoresistive random access memory (MRAM) is a non-volatile randomaccess memory technology in which data is stored by magnetic storageelements. These elements are typically formed from two ferromagneticplates, each of which can hold a magnetization, separated by a thindielectric layer, i.e., the tunnel barrier. One of the two plates is apermanent magnetic set to a particular polarity; the other plate'smagnetization can be changed to match that of an external field to storememory. Such a configuration is known as a magnetic tunnel junction(MTJ) pillar.

Conductive pedestals are used in such memory devices to create aphysical distance between the bottom electrode and the MTJ pillar. Inthe prior art, a conductive layer (typically having a lower atomicweight than the bottom electrode) is formed on a surface of a bottomelectrode, and then a MTJ stack is formed on the conductive layer. Anetch is then performed to provide a MTJ pillar and a conductive pedestalthat has a ‘foot’ or tapered sidewall. This tapered conductive pedestalcan pose problems for final cleaning of the sidewall of the MTJ pillarthrough ion beam etching (IBE) at a different angle, as it is moresusceptible to being resputtered and deposited on the sidewall of theMTJ pillar. If resputtered conductive metal particles deposit on thetunnel barrier material of the MTJ pillar, electrical shorts may arise,which is a common failure mode. There is thus a need for a method thatcan prevent the deposition of such resputtered conductive metalparticles from the tapered conductive pedestal structure on the sidewallof the MTJ pillar.

SUMMARY

An undercut conductive pedestal structure having a concave sidewall isformed between a bottom electrode and a MTJ pillar. The geometric natureof such a conductive pedestal structure makes the pedestal structureunlikely to be resputtered and deposited on the sidewall of the MTJpillar, especially the sidewall of the tunnel barrier material of theMTJ pillar. Thus, electrical shorts caused by depositing resputteredconductive metal particles on the sidewall of the tunnel barriermaterial of the MTJ pillar are substantially reduced.

In one aspect of the present application, a magnetic tunnel junction(MTJ) containing device such as, for example, a memory device or asensor is provided. In one embodiment, the MTJ containing deviceincludes a conductive pedestal structure having a concave sidewalllocated on a bottom electrode. A magnetic tunnel junction (MTJ) pillaris located on the pedestal structure, and a top electrode is located onthe MTJ pillar.

In another aspect of the present application, a method of forming amagnetic tunnel junction (MTJ) containing device is provided. In oneembodiment, the method includes forming a structure including aconductive layer located on a bottom electrode, a multilayered MTJ stacklocated on the conductive layer, and a top electrode located on themultilayered MTJ stack. The multilayered MTJ stack and the underlyingconductive layer are then etched to provide a MTJ pillar and aconductive pedestal having a tapered sidewall, respectively. Next, apassivation material spacer is formed on a sidewall of each of the topelectrode and the MTJ pillar, and on an upper portion of the taperedsidewall of the conductive pedestal. The conductive pedestal having thetapered sidewall is then etched to provide a conductive pedestalstructure having a concave sidewall.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of an exemplary MTJ containing deviceof the present application and during an early stage of fabrication, theMTJ containing device including a conductive layer located on a surfaceof a bottom electrode, a multilayered MTJ stack located on theconductive layer, and a top electrode located on the multilayered MTJstack.

FIG. 2 is a cross sectional view of the exemplary MTJ containing deviceof FIG. 1 after etching the multilayered MTJ stack and the underlyingconductive layer to provide a MTJ pillar and a conductive pedestalhaving a tapered sidewall, respectively.

FIG. 3 is a cross sectional view of the exemplary MTJ containing deviceof FIG. 2 after forming a passivation material layer on the physicallyexposed surfaces of the top electrode, the MTJ pillar and the conductivepedestal having the tapered sidewall.

FIG. 4 is a cross sectional view of the exemplary memory device of FIG.3 after etching the passivation material layer to provide a passivationmaterial spacer on a sidewall of each of the top electrode and the MTJpillar, and on an upper portion of the tapered sidewall of theconductive pedestal.

FIG. 5 is a cross sectional view of the exemplary MTJ containing deviceof FIG. 4 after etching the conductive pedestal having the taperedsidewall to provide a conductive pedestal structure having a concavesidewall.

DETAILED DESCRIPTION

The present application will now be described in greater detail byreferring to the following discussion and drawings that accompany thepresent application. It is noted that the drawings of the presentapplication are provided for illustrative purposes only and, as such,the drawings are not drawn to scale. It is also noted that like andcorresponding elements are referred to by like reference numerals.

In the following description, numerous specific details are set forth,such as particular structures, components, materials, dimensions,processing steps and techniques, in order to provide an understanding ofthe various embodiments of the present application. However, it will beappreciated by one of ordinary skill in the art that the variousembodiments of the present application may be practiced without thesespecific details. In other instances, well-known structures orprocessing steps have not been described in detail in order to avoidobscuring the present application.

It will be understood that when an element as a layer, region orsubstrate is referred to as being “on” or “over” another element, it canbe directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” or “directly over” another element, there are no interveningelements present. It will also be understood that when an element isreferred to as being “beneath” or “under” another element, it can bedirectly beneath or under the other element, or intervening elements maybe present. In contrast, when an element is referred to as being“directly beneath” or “directly under” another element, there are nointervening elements present.

Referring now to FIG. 1, there is illustrated an exemplary magnetictunnel junction (MTJ) containing device of the present application andduring an early stage of fabrication. Exemplary MTJ containing devicesinclude, but are not limited to, memory devices (e.g., MRAM orspin-transfer torque (STT) MRAM), or sensors such as, for example,pressure sensors. Notably, the exemplary MTJ containing device shown inFIG. 1 includes a conductive layer 16 located on a surface of a bottomelectrode 14, a multilayered MTJ stack 18 located on the conductivelayer 16, and a top electrode 26 located on the multilayered MTJ stack18. It is noted that the drawings of the present application illustratea device area in which a MTJ containing device will be formed. A non-MTJcontaining device area may be located adjacent to the MTJ containingdevice area illustrated in the drawings of the present application. Itis also noted that while a single bottom electrode 14 and a single topelectrode 26 are described and illustrated, the present application canbe used when a plurality of bottom electrodes 14 and a plurality of topelectrodes 26 are formed.

As is shown, the bottom electrode 14 is located on a surface of anelectrically conductive structure 12 that is embedded in an interconnectdielectric material layer 10. Although not shown, a diffusion barrierliner can be formed on the sidewalls and bottom wall of the electricallyconductive structure 12. Collectively, the electrically conductivestructure 12, the diffusion barrier liner (if present), and theinterconnect dielectric material layer 10 provide an interconnect levelIt is noted that at least one other interconnect level and/or amiddle-of-the-line (MOL) level may be located beneath the interconnectlevel including the interconnect dielectric material layer 10, theelectrically conductive structure 12, and, if present, the diffusionbarrier liner. These other levels are not shown for clarity.

The interconnect dielectric material layer 10 can be composed of anyinterconnect dielectric material including, for example, silicondioxide, silsesquioxanes, C doped oxides (i.e., organosilicates) thatincludes atoms of Si, C, O and H, thermosetting polyarylene ethers, ormultilayers thereof. The term “polyarylene” is used in this applicationto denote aryl moieties or inertly substituted aryl moieties which arelinked together by bonds, fused rings, or inert linking groups such as,for example, oxygen, sulfur, sulfone, sulfoxide, carbonyl and the like.

The electrically conductive structure 12 is composed of an electricallyconductive metal or metal alloy. Examples of electrically conductivematerials that may be used in the present application include copper(Cu), aluminum (Al), or tungsten (W), while an example of anelectrically conductive metal alloy is a Cu—Al alloy.

In some embodiments, a diffusion barrier liner is formed along thesidewalls and a bottom wall of the electrically conductive structure 12.In some embodiments, no diffusion barrier liner is present. Thediffusion barrier liner is composed of a diffusion barrier material(i.e., a material that serves as a barrier to prevent a conductivematerial such as copper from diffusing there through). Examples ofdiffusion barrier materials that can be used in providing the diffusionbarrier liner include, but are not limited to, Ta, TaN, Ti, TiN, Ru,RuN, RuTa, RuTaN, W, or WN. In some embodiments, the diffusion barriermaterial may include a material stack of diffusion barrier materials. Inone example, the diffusion barrier material may be composed of a stackof Ta/TaN.

The interconnect level including the interconnect dielectric materiallayer 10, the electrically conductive structure 12, and, if present,diffusion barrier liner may be formed utilizing conventional processesthat are well-known to those skilled in the art including, for example,a damascene process. So as not to obscure the method of the presentapplication, the techniques used to form the interconnect levelincluding the interconnect dielectric material layer 10, theelectrically conductive structure 12, and, if present, the diffusionbarrier liner are not provided herein.

In some embodiments (not shown), the bottom electrode 14 is located on arecessed surface of the electrically conductive structure 12. In such anembodiment, and prior to forming the bottom electrode 14, an upperportion of the electrically conductive structure 12 is removed utilizinga recess etching process, and thereafter the bottom electrode 14 isformed upon the recessed surface of the electrically conductivestructure 12. In such an embodiment, the bottom electrode 14 would belocated on an entirety of the recessed topmost surface of theelectrically conductive structure 12. Also, and in such an embodiment,the bottom electrode 14 would have a topmost surface that is coplanarwith a topmost surface of the interconnect dielectric material layer 10,and an upper portion of the interconnect dielectric material layer 10would be laterally adjacent to each sidewall of the bottom electrode 14.Further, and in such an embodiment, dielectric capping layer 13 shown inFIG. 1 can be omitted from the structure.

In other embodiments and as illustrated in FIG. 1, the bottom electrode14 is formed on a non-recessed surface of the electrically conductivestructure 12. In such an embodiment, a dielectric capping layer 13 islocated laterally adjacent to the bottom electrode 14 and on a surfaceof the interconnect dielectric material layer 10. In this embodiment, asmaller width bottom electrode 14 can be provided that does not coverthe entirety of the topmost surface of the electrically conductivestructure 12.

When present, the dielectric capping layer 13 may be composed of anydielectric material such as, for example, SiC, Si₃N₄, SiO₂, a carbondoped oxide, a nitrogen and hydrogen doped silicon carbide SiC(N,H) ormultilayers thereof. The dielectric capping layer 13 can be formedutilizing a conventional deposition process such as, for example,chemical vapor deposition (CVD), plasma enhanced chemical vapordeposition (PECVD), chemical solution deposition, evaporation, or plasmaenhanced atomic layer deposition (PEALD). In some embodiments, and asexplained above, the dielectric capping layer 13 may be omitted from theexemplary MTJ containing device. In some embodiments and as isillustrated in FIG. 1, the bottom electrode 14 has a topmost surfacethat is coplanar with a topmost surface of a dielectric capping layer 13that may be present laterally adjacent to the bottom electrode 14 and ona topmost surface of the interconnect dielectric material layer 10.

The dielectric capping layer 13 may be formed prior to, or after,forming the bottom electrode 14. In embodiments when the dielectriccapping layer 13 is formed prior to the bottom electrode 14, a blanketlayer of dielectric capping material is formed and thereafter an openingis formed (by photolithography and etching) in the dielectric cappingmaterial. The bottom electrode 14, as defined below, is then formed inthe opening. In such an embodiment, the bottom electrode 14 is formed bydeposition, followed by a planarization process. In embodiments in whichthe bottom electrode 14 is formed prior to the dielectric capping layer13, the bottom electrode is formed by deposition and patterning, andthereafter the dielectric capping material is deposited and a subsequentplanarization process may be performed.

Bottom electrode 14, which is present on a surface of the electricallyconductive structure 12, may be composed of a conductive material suchas, for example, Ta, TaN, Ti, TiN, Ru, RuN, RuTa, RuTaN, Co, CoWP, CoN,W, WN or any combination thereof. The bottom electrode 14 may have athickness from 2 nm to 25 nm; other thicknesses are possible and can beused in the present application as the thickness of the bottom electrode14. The bottom electrode 14 may be formed by a deposition process suchas, for example, sputtering, atomic layer deposition (ALD), chemicalvapor deposition (CVD), plasma enhanced chemical vapor deposition(PECVD) or physical vapor deposition (PVD). An etch back process, aplanarization process (such as, for example, chemical mechanicalpolishing), or a patterning process (such as, for example, lithographyand etching) may follow the deposition of the conductive material thatprovides the bottom electrode 14.

The conductive layer 16 includes any conductive material. In someembodiments, a material that has, or combination of materials that have,a lower atomic weight than the conductive material that provides thebottom electrode 14 can be used as the conductive layer 16. Typically,the conductive material that provides the conductive layer 16 has alower sticking coefficient than that of the bottom electrode 14.Illustrative examples of conductive materials that can be used as theconductive layer 16 include one of the conductive materials mentionedabove for the bottom electrode 14 with the proviso that the selectedconductive material of the conductive layer 16 has a lower atomic weightthan the conductive material of bottom electrode 14. In one example, andwhen the bottom electrode 14 is composed of TaN, then the conductivelayer 16 is composed of Ti or TiN, or W.

The conductive layer 16 can be formed by a deposition process such as,for example, sputtering, atomic layer deposition (ALD), chemical vapordeposition (CVD), plasma enhanced chemical vapor deposition (PECVD) orphysical vapor deposition (PVD). The thickness of the conductive layer16 may be from 20 nm to 500 nm. Other thicknesses besides the specifiedrange can also be employed as the thickness of the conductive layer 16.

The MTJ stack 18 includes at least a magnetic reference layer 20, atunnel barrier layer 22, and a magnetic free layer 24 as configured inFIG. 1. Other MTJ stack 18 configurations are possible such as, forexample, the magnetic free layer 24 being located at the bottom of theMTJ stack 18 and the magnetic reference layer 20 being at the top of theMTJ stack 18. In some embodiments (not shown), the MTJ stack 18 may alsoinclude a non-magnetic spacer layer located on the magnetic free layer,a second magnetic free layer located on the non-magnetic spacer layer,and/or a MTJ cap layer located on the magnetic free layer 24 or on thesecond magnetic free layer. The various material layers of the MTJ stack18 can be formed by utilizing one or more deposition processes such as,for example, plating, sputtering, plasma enhanced atomic layerdeposition (PEALD), plasma enhanced chemical vapor deposition (PECVD) orphysical vapor deposition (PVD).

The magnetic reference layer 20 has a fixed magnetization. The magneticreference layer 20 may be composed of a metal or metal alloy (or a stackthereof) that includes one or more metals exhibiting high spinpolarization. In alternative embodiments, exemplary metals for theformation of the magnetic reference layer 20 include iron, nickel,cobalt, chromium, boron, or manganese. Exemplary metal alloys mayinclude the metals exemplified by the above. In another embodiment, themagnetic reference layer 20 may be a multilayer arrangement having (1) ahigh spin polarization region formed from of a metal and/or metal alloyusing the metals mentioned above, and (2) a region constructed of amaterial or materials that exhibit strong perpendicular magneticanisotropy (strong PMA). Exemplary materials with strong PMA that may beused include a metal such as cobalt, nickel, platinum, palladium,iridium, or ruthenium, and may be arranged as alternating layers. Thestrong PMA region may also include alloys that exhibit strong PMA, withexemplary alloys including cobalt-iron-terbium, cobalt-iron-gadolinium,cobalt-chromium-platinum, cobalt-platinum, cobalt-palladium,iron-platinum, and/or iron-palladium. The alloys may be arranged asalternating layers. In one embodiment, combinations of these materialsand regions may also be employed.

The tunnel barrier layer 22 is composed of an insulator material and isformed at such a thickness as to provide an appropriate tunnelingresistance. Exemplary materials for the tunnel barrier layer 22 includemagnesium oxide, aluminum oxide, and titanium oxide, or materials ofhigher electrical tunnel conductance, such as semiconductors orlow-bandgap insulators.

The magnetic free layer 24 may be composed of a magnetic material (or astack of magnetic materials) with a magnetization that can be changed inorientation relative to the magnetization orientation of the magneticreference layer 20. Exemplary magnetic materials for the magnetic freelayer 24 include alloys and/or multilayers of cobalt, iron, alloys ofcobalt-iron, nickel, alloys of nickel-iron, and alloys ofcobalt-iron-boron.

If present, the non-magnetic metallic spacer layer is composed of anon-magnetic metal or metal alloy that allows magnetic information to betransferred therethrough and also permits the two magnetic free layersto couple together magnetically, so that in equilibrium the first andsecond magnetic free layers are always parallel. The non-magneticmetallic spacer layer allows for spin torque switching between the firstand second magnetic free layers.

If present, the second magnetic free layer may include one of themagnetic materials mentioned above for magnetic free layer 24. In oneembodiment, the second magnetic free layer is composed of a samemagnetic material as the magnetic free layer 24. In another embodiment,the second magnetic free layer is composed of a magnetic material thatis compositionally different from the magnetic free layer 24.

If present, the MTJ cap layer can be composed of Nb, NbN, W, WN, Ta,TaN, Ti, TiN, Ru, Mo, Cr, V, Pd, Pt, Rh, Sc, Al or other high meltingpoint metals or conductive metal nitrides. The MTJ cap layer may have athickness from 2 nm to 25 nm; other thicknesses are possible and can beused in the present application as the thickness of the MTJ cap layer.

The top electrode 26 may be composed of one of the conductive materialsmentioned above for the bottom electrode 14. The conductive materialthat provides the top electrode 26 is typically compositionallydifferent from the optional MTJ cap layer. The top electrode 26 can havea thickness within the thickness range mentioned above for the bottomelectrode 14. The top electrode 26 may be formed utilizing one of thedeposition processes mentioned above in providing the bottom electrode14, followed by performing a patterning process, such as, for example,photolithography and etching.

Referring now to FIG. 2, there is illustrated the exemplary memorydevice of FIG. 1 after etching the multilayered MTJ stack 18 and theunderlying conductive layer 16 to provide a MTJ pillar 18P and aconductive pedestal 16P having a tapered sidewall, respectively. In thepresent application, the top electrode 26 serves as an etch mask. Theetching of the multilayered MTJ stack 18 and the underlying conductivelayer 16 comprises one or more etching steps. The one or more etchingsteps may include one or more reactive ion etching processes. The MTJpillar 18P and the top electrode 26 are typically cylindrical in shape.However, other asymmetric shapes are possible and can be utilized in thepresent application.

As is shown, the MTJ pillar 18P has a sidewall that is verticallyaligned to the sidewall of the top electrode 26. The MTJ pillar 18Pincludes at least a remaining portion of the magnetic reference layer 20(hereinafter magnetic reference material 20P), a remaining portion ofthe tunnel barrier layer 22 (hereinafter tunnel barrier material 22P)and a remaining portion of the magnetic free layer 24 (hereinaftermagnetic free material 24P). In some embodiments, the MTJ pillar 18P mayalso include a remaining portion of the non-magnetic spacer, a remainingportion of the second magnetic reference layer, and/or a remainingportion of the MTJ cap layer.

The tapered sidewall of the conductive pedestal 16P extends outward froma topmost surface of the conductive pedestal 16P to a bottommost surfaceof the conductive pedestal 16P. An angle, a, between the bottommostsurface of the conductive pedestal 16P, and the tapered sidewall can befrom 25° to 85°. Conductive pedestal 16P has a lateral dimension that isgreater than a lateral dimension of the MTJ pillar 18P, the topelectrode 26 and the bottom electrode 14. The conductive pedestal 16Phas a pyramidal shape having a thickness that decreases from thebottommost surface upwards to the topmost surface.

In the prior art and in order to reduce the taper of the pedestalstructure, an angled IBE process is now typically performed. However, ifsuch an angled IBE is used, conductive metal particles are resputteredfrom the pedestal structure and such resputtered metal particles candeposit on the sidewall of the MTJ pillar. As mentioned above, suchresputtered conductive metal particles that deposit on the sidewall ofthe MTJ pillar causes electrical shorts. Thus, and in the presentapplication, such an angled IBE is not performed at this stage of thepresent application.

Referring now to FIG. 3, there is illustrated the exemplary memorydevice of FIG. 2 after forming a passivation material layer 28L on thephysically exposed surfaces of the top electrode 26, the MTJ pillar 18Pand the conductive pedestal 16P. The passivation material layer 28L alsoextends onto the physically exposed surface of either the dielectriccapping layer 13 or the interconnect dielectric material layer 10.

The passivation material layer 28L is composed of a dielectric material.In one example, the passivation material layer 28L is composed ofsilicon nitride. In another example, the passivation material layer 28Lmay be composed of a dielectric material that contains atoms of silicon,carbon and hydrogen. In some embodiments, and in addition to atoms ofcarbon and hydrogen, the dielectric material may include atoms of atleast one of nitrogen and oxygen. In other embodiments, and in additionto atoms of silicon, nitrogen, carbon and hydrogen, the dielectricmaterial may include atoms of boron. In one example, the passivationmaterial layer 28L may be composed of an nBLOK dielectric material thatcontains atoms of silicon, carbon, hydrogen, nitrogen and oxygen. Inalternative example, the passivation material layer 28L may be composedof a SiBCN dielectric material that contains atoms of silicon, boron,carbon, hydrogen, and nitrogen.

The passivation material layer 28L can be formed utilizing a depositionprocess such as, for example, PECVD, PVD, or PEALD. The passivationmaterial layer 28L may have a thickness from 10 nm to 200 nm. Otherthicknesses are possible and can be employed as the thickness of thepassivation material layer 28L. In some embodiments, the passivationmaterial layer 28L has a conformal thickness. The term “conformal”denotes that a material layer has a vertical thickness along horizontalsurfaces that is substantially the same (i.e., within ±5%) as thelateral thickness along vertical surfaces.

Referring now to FIG. 4, there is illustrated the exemplary memorydevice of FIG. 3 after etching the passivation material layer 28L toprovide a passivation material spacer 28 on the sidewall of each of thetop electrode 26 and the MTJ pillar 18P, and on an upper portion of thetapered sidewall of the conductive pedestal 16P. The etching of thepassivation material layer 28L may be performed utilizing any spaceretching process such as, for example, reactive ion etching, that isselective for removing passivation material.

Referring now to FIG. 5, there is illustrated the exemplary memorydevice of FIG. 4 after etching the conductive pedestal 16P having thetapered sidewall to provide a conductive pedestal structure 16S having aconcave sidewall 17. The conductive pedestal structure 16S has anhour-glass shape. That is, the conductive pedestal structure has anundercut along the outermost sidewall as shown in FIG. 5; the undercutmay extend inwards from 2 nm to 30 nm from the outermost sidewall of thepassivation material spacer 28. The concave sidewall 17 of theconductive pedestal structure 16S is shielded from impinging ions by theoverhang of the elements that are located above the conductive pedestalstructure 16S. The geometric nature of the conductive pedestal structure16S makes the conductive pedestal structure 16S of the presentapplication unlikely to be resputtered and deposited on the sidewall ofthe MTJ pillar 18P, especially the sidewall of the tunnel barrier 22P ofthe MTJ pillar 18P. Thus, electrical shorts caused by depositingresputtered conductive metal particles are substantially eliminated.

The etching used in this step of the present application is selective inremoving the conductive material that provides the conductive pedestal16P. In one example, a reactive ion etch can be used at this point ofthe present application. The etching used in this step of the presentapplication uses the passivation material spacer 28 and the topelectrode 26 has an etch mask.

In some embodiments, the passivation material spacer 28 may be thinnedduring this step of the present application. The thinned or non-thinnedpassivation material spacer 28 is located on the sidewall of each of thetop electrode 26 and the MTJ pillar 18P and contacts a topmost surfaceof the conductive pedestal structure 16S. As is shown in FIG. 5, theconcave sidewall 17 of the conductive pedestal structure 16S is locateddirectly beneath the passivation material spacer 28. The conductivepedestal structure 16S does not extend beyond an outermost sidewall ofthe thinned or non-thinned passivation material spacer 28.

Notably, FIG. 5 illustrates an exemplary memory device that includes aconductive pedestal structure 16S having a concave sidewall 17 locatedon a bottom electrode 14. A magnetic tunnel junction (MTJ) pillar(20P/22P/24P) is located on the conductive pedestal structure 16S, and atop electrode 26 is located on the MTJ pillar (20P/22P/24P). Stated inother terms, an hour-glass shaped conductive pedestal structure 16S islocated between the bottom electrode 14 and the MTJ pillar 18P.

At this point of the present application, an angled IBE process, toremove residual metallic materials from the tunnel barrier material 22P,can now be performed. Unlike the prior art, and due to the geometry ofthe pedestal structure 16S and the passivation spacer 28, substantiallyno conductive metal particles that may be resputtered from the pedestalstructure 16S deposit on the sidewall of the MTJ pillar 18P thusreducing the possibility of electrical shorts caused by the redepositconductive metal particles. Thus, and in the present application,improved device performance, in terms of a reduction in failure mode,can be obtained.

Although not shown, another electrically conductive structure is formedcontacting a surface of the top electrode 26. This other electricallyconductive structure is embedded in another interconnect dielectricmaterial that is formed laterally adjacent to, and above, the stackincluding the pedestal structure 16S, the MTJ pillar 18P, and the topelectrode 26.

While the present application has been particularly shown and describedwith respect to preferred embodiments thereof, it will be understood bythose skilled in the art that the foregoing and other changes in formsand details may be made without departing from the spirit and scope ofthe present application. It is therefore intended that the presentapplication not be limited to the exact forms and details described andillustrated, but fall within the scope of the appended claims.

1. A magnetic tunnel junction (MTJ) containing device comprising: aconductive pedestal structure having a concave sidewall, wherein theconductive pedestal structure is located on a bottom electrode; amagnetic tunnel junction (MTJ) pillar located on the conductive pedestalstructure; a top electrode located on the MTJ pillar; and a passivationmaterial spacer located on the sidewall of each of the top electrode andthe MTJ pillar and contacting a topmost surface of the conductivepedestal structure.
 2. (canceled)
 3. The MTJ containing device of claim1, wherein the concave sidewall of the conductive pedestal structure islocated directly beneath the passivation material spacer.
 4. The MTJcontaining device of claim 1, wherein the conductive pedestal structurehas a hour-glass shape.
 5. The MTJ containing device of claim 1, whereinthe bottom electrode is located on a surface of an electricallyconductive structure, and the electrically conductive structure isembedded in an interconnect dielectric material layer.
 6. The MTJcontaining device of claim 1, wherein the conductive pedestal structureis located on a non-recessed surface of the bottom electrode, andwherein a dielectric capping layer is located laterally adjacent to thebottom electrode.
 7. The MTJ containing device of claim 1, wherein theMTJ pillar comprises a magnetic reference material, a tunnel barriermaterial, and a magnetic free material, wherein the magnetic referencematerial forms an interface with the conductive pedestal structure. 8.The MTJ containing device of claim 1, wherein the conductive pedestalstructure is composed of a conductive material having a lower atomicweight than a conductive material that provides the bottom electrode. 9.The MTJ containing device of claim 1, wherein no resputtered conductivemetal particles are present on a sidewall of the MTJ pillar.
 10. The MTJcontaining device of claim 1, wherein the conductive pedestal structure,the MTJ pillar, and the top electrode are components of a memory deviceor a sensor. 11.-20. (canceled)
 21. A magnetic tunnel junction (MTJ)containing device comprising: a conductive pedestal structure having aconcave sidewall, wherein the conductive pedestal structure is locatedon a bottom electrode; a magnetic tunnel junction (MTJ) pillar locatedon the conductive pedestal structure; and a top electrode located on theMTJ pillar, wherein the bottom electrode is located on a surface of anelectrically conductive structure, and the electrically conductivestructure is embedded in an interconnect dielectric material layer. 22.A magnetic tunnel junction (MTJ) containing device comprising:conductive pedestal structure having a concave sidewall, wherein theconductive pedestal structure is located on a non-recessed surface of abottom electrode; a magnetic tunnel junction (MTJ) pillar located on theconductive pedestal structure; a top electrode located on the MTJpillar; and a dielectric capping layer located laterally adjacent to thebottom electrode.